TclMilter

TclMilter is a powerful software package designed for Tcl that enables developers to implement custom scripted message rewriting and spam filtering processes using SendMail's Milter API. This API is capable of handling complex filtering processes and is a popular choice among developers. This package is written in C and requires a thread-enabled Tcl build, due to Milter's threading requirements.

It is important to note that you can only run, configure, or register callbacks for a milter from the first thread/interpreter the package is loaded into. However, to stop the milter from within Tcl, the package must be loaded in another thread. Only the "milter stop" command will function in secondary threads.

TclMilter is released under the GNU General Public License (GPL), and users can find details of this license in the file "license.terms." Some of the key features of TclMilter include:

- The smfi_opensocket command is replaced with milter main as an interface to smfi_main.
- The commands smfi_setconn, smfi_settimeout, smfi_setbacklog, and smfi_setdbg and settings typically provided through smfi_main are instead provided as milter configure options.
- Unlike libmilter, the smfi_register command can register and unregister callbacks at any time.
- TclMilter's milter setpriv command uses a hash table to set individual, custom variables with data to associate with a context, unlike smfi_setpriv that uses a single data storage value.
- The context provided to callbacks is an actual Tcl command that can be used to interact with the context.

This new release of TclMilter also includes updated TEA support files to version 3.6, and the configure script regenerated to fix configure errors under Linux.

Overall, TclMilter is an excellent package for developing custom scripted message rewriting and spam filtering processes using SendMail's Milter API. Its features and capabilities make it a popular choice among developers who require complex filtering processes.